“The primary mandate I had for myself in making this decision was to have it based on the potential for my growth as a player,” the forward wrote on the Players Tribune website.

“…But I am also at a point in my life where it is of equal importance to find an opportunity that encourages my evolution as a man: moving out of my comfort zone to a new city and community which offers the greatest potential for my contribution and personal growth.

“With this in mind, I have decided that I am going to join the Golden State Warriors.”

The Thunder had hoped to keep Durant, who was a free agent. The Warriors, the 2015 NBA champions, were beaten in game seven of this year’s finals by the LeBron James-inspired Cleveland Cavaliers. Golden State now have a hugely-powerful line-up with Durant joining NBA MVP Stephen Curry, as well as fellow All-Stars Klay Thompson and Draymond Green. The Warriors are likely to make room for Durant by letting Harrison Barnes join the Dallas Mavericks on a reported four year, $95m deal. Australian center Andrew Bogut, who is due $11m next season, removed references to the Warriors from his Twitter page in the last week and also appears set to leave the team.

“Oklahoma City truly raised me,” Durant wrote. “It taught me so much about family as well as what it means to be a man.”

He added that “it really pains me to know that I will disappoint so many people with this choice”, and said he would miss Oklahoma City. The Thunder were just one game from beating the Warriors in this year’s Western Conference finals, and many fans will see Durant’s decision to move to Golden State as a betrayal of a team with a talented young roster.

“I will forever cherish the relationships within the organization,” he added, “the friends and team-mates that I went to war with on the court for nine years, and all the fans and people of the community.”

The Thunder chairman, Clayton I Bennett paid tribute to Durant’s time with the team. “Kevin’s contributions to our organization during his nine years were profound, on and off the court,” Bennett said in a statement. “He helped the Thunder grow and succeed in immeasurable ways and impacted the community just the same.

“We thank him for his leadership, his play, and how he represented Oklahoma City and the entire state of Oklahoma.”

As well as gaining a brilliant player, the Warriors have rid themselves of a dangerous opponent: Durant averaged 30 points against them in this year’s Western Conference finals. Across his career the 27-year-old has averaged 27.4 points-per game - that figure rises to 28.8 in the playoffs.